Saturday, November 19, 2011

naxa nmv-155 :: slackware (mini-slack)

Links:

Let's see if we can get anywhere with this inexpensive media player. Sometimes they're in a bargain bin for $15, on up to $50 in other places (probably $5 of parts in the unit). I found it for $25, which was a bit steep, but worth the experiment. Reading around a bit first, it appears that the two largest issues are usb recognition and media formatting. It's got a 4GB internal, and room for a card as well. But it's a cheap player and it's accordingly picky about file formats. Videos supposedly have to be perfectly packaged to play. I was excited to see that it will apparently read PDF's (Edit: this was misadvertised; it reads only basic text files) too, in addition to mp3's, movies, and photos. Battery life is reasonable so, if I can get this going, I may have a nice solution for watching movies while flying.

unboxing

Unit comes without any cover but fits perfectly into a G1 holder (remaining after I had a G1 stolen). A USB -> micro-USB connector cable, a 300mA AC->micro-USB charger, earbuds, stylus (a plastic dental pick also works), Windows disk, and a small manual.

usb detection/connection

Threw out the Windows disk and plugged in the USB, and no auto-recognition took place in any file managers. Nothing in lsusb. Seeing nothing in udevmonitor either. I swapped USB cables with a known good one I have for a different device and suddenly it shows up in my file manager, no problems. It's identified there as "GENERIC USB DISK DEVICE Music Player" (3.5GB). We're already at less than the advertised 4GB. In lsusb, it appears as
10d6:1101 Actions Semiconductor Co., Ltd D-Wave 2GB MP4 Player / AK1025 MP3/MP4 Player
This is probably most accurate. It tells me I've been ripped off, essentially. Appears I have one of those Chinese 2GB devices that was hacked to show twice its real capacity. Another system check also shows 3.7 GB, but I'd bet against it
# df
/dev/sdc 3709840 2084 3707756 1% /media/disk
Summary: Threw away the included USB->micro-USB cable and the Windows disk, lowered my expectation to a little less than 2GB for this (likely) piece of shiat.

video

Let's upload something less than 2GB and see if it plays.
  • MKV - First-up, a 1.4GB sports vid coded in MKV. Result: the file is not even detected in the device file manager. Can't even be seen there.
  • AVI - Second, we'll do a standard AVI, let's go. Here's the encoding and resolution
    Stream #0.0: Video: mpeg4, yuv420p, 608x336
    Stream #0.1: Audio: mp3, 48000 Hz, stereo, s16, 96 kb/s
    Wondering if the reason the previous file couldn't be read was whitespace in its title, so this 676MB file contains no whitespace.

    This file appeared in the device. I attempted to play it, but the NAXA displayed a "file format error". Going to eject out of this process and research.

more video

Research will be making a short vid with the device and see if that can playback. If so, I'll duplicate its settings with ffmpeg or mencoder.

So I made a little vid on the device. It packages raw vid into AVI containers. It plays on the device - here's the skinny:
Duration: 00:00:17.93, start: 0.000000, bitrate: 551 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 320x240
Stream #0.1: Audio: mp3, 16000 Hz, stereo, s16, 64 kb/s
So 320x240 and 551k bitrate, and only 64 k on the sound. These settings aren't sufficient for movies, but we'll see if we can get something into that. Here was the first shot, though I didn't do anything with B frames or so forth, just tried to shrink one:
$ ffmpeg -i some.avi -target ntsc-dvd -vcodec mpeg4 -s 320x240 -b 1500k -acodec libmp3lame -ar 44100 -ab 192k -ac 2 -vol 300 dinky.avi
This encoded without errors but playback produced errors and was without video or a duration stamp, though audio was OK. Playback errors - many of these:
MPEG: bad sequence header missing marker bit!
All of this I think is something to do with trying to match MP4, which is what the device encodes. Perhaps with Q scale...I'll keep playing with it.

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